Coupling Mechanism for Medical Devices

ABSTRACT

A releasable coupling mechanism for coupling a delivery catheter and a dilator. The delivery catheter comprising a first mating member at the proximal end and the dilator comprising a second mating member at the proximal end. The proximal end of the first mating member comprises a first coupling means for releasably receiving a second coupling means which is positioned at a distal end of the second mating member. The first mating member further comprising a coupling member the coupling member comprising a pair of engagement members positioned on opposing sides of the coupling member and configured to releasably engage the second coupling means. The first mating member further comprising at least one indicia perpendicular from the pair of engagement members. The indicia indicate an orientation of the first mating member such that the second mating member disengages from the coupling member by simultaneously deflecting the pair of engagement members.

The disclosure relates to systems and methods that incorporate couplingmechanisms that allow for coupling two mating members, such as twomedical devices, such as introducers, sheaths, dilators and the like forpart of a procedure. More specifically, the disclosure relates toreleasable coupling mechanisms, specifically snap-fit mechanisms, toallow for releasably coupling two medical devices such as a dilator andsheath for part of a procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be readily understood, embodiments ofthe invention are illustrated by way of examples in the accompanyingdrawings, in which:

FIG. 1A is a perspective view of a hub for a medical device, comprisinga coupling mechanism in accordance with an embodiment of the presentinvention and further showing a second device at least partiallyinserted into the hub;

FIG. 1B shows a cross sectional view of the hub of FIG. 1A and thecoupling mechanism incorporated therein, in accordance with anembodiment of the present invention;

FIG. 1C is a perspective view of the hub, showing a coupling mechanismcomprising guides and co-operating features for enabling coupling of twomedical devices in accordance with an embodiment of the presentinvention;

FIG. 1D is a side view of a device, for example a dilator, inserted intothe hub of a second medical device, for example a sheath, wherein thesheath comprises a coupling mechanism in accordance with an embodimentof the present invention;

FIG. 2A(i) is a perspective view of a hub with a coupling mechanism,showing another device about to be inserted into the hub;

FIG. 2A(ii) is a cross sectional view of the hub of FIG. 2A(i), showingthe other device partially inserted through the coupling mechanism;

FIG. 2B(i) is a perspective view of a hub with a coupling mechanism,showing another device about to be inserted into the hub;

FIG. 2B(ii) is a cross sectional view of the hub of FIG. 2B(i), showingthe other device partially inserted through the coupling mechanism;

FIGS. 3A(i), 3A(ii) and 3A(iii) are, respectively, an exploded view, aperspective view and a cross section through a hub containing anembodiment of a coupling mechanism of the present invention;

FIGS. 3B and 3C are, respectively, cross sectional views of a devicebeing inserted through an embodiment of a coupling mechanism and thedevice being retracted therefrom;

FIGS. 3D(i) and 3D(ii) are perspective exploded views illustratingvarious features of a hub and coupling mechanism of the presentinvention;

FIGS. 4A(i), 4A(ii) and 4A(iii) are, respectively, an exploded view, aperspective view and a cross section through a hub containing anembodiment of a coupling mechanism of the present invention;

FIG. 4A(iv) is a perspective view of an embodiment of a hub and couplingmechanism of the present invention;

FIGS. 4B and 4C, respectively, are cross sectional views showing adevice that is being inserted through an embodiment of a couplingmechanism, and the device being removed from the coupling mechanism;

FIGS. 5A(i), 5A(ii) and 5A(iii) are, respectively, a perspective view,an exploded view, and a cross section through a hub containing anembodiment of a coupling mechanism of the present invention, as well asa device inserted through the coupling mechanism;

FIG. 5A(iv) is a perspective view of an embodiment of a hub and couplingmechanism of the present invention;

FIGS. 5B and 5C, respectively, are cross sectional views showing adevice being inserted through an alternate embodiment of a couplingmechanism, and the device being removed from the coupling mechanism;

FIGS. 5D(i), 5D(ii) and 5D(iii) are, respectively, an exploded view, aperspective view and a cross section through a hub containing anembodiment of a coupling mechanism of the present invention;

FIG. 5D(iv) is a perspective view of an embodiment of a hub and couplingmechanism of the present invention;

FIGS. 5E(i) and 5E(ii) show, respectively, cross sectional andperspective views of an embodiment of a housing and a coupling mechanismof the present invention;

FIGS. 5F(i) and 5F(ii) are cross sectional illustrations of a devicebeing inserted through an embodiment of a coupling mechanism of thepresent invention and being removed therefrom;

FIGS. 6A(i) and 6A(iv) are, respectively, perspective views of a devicepartially and fully inserted into a hub comprising an embodiment of acoupling mechanism of the present invention;

FIGS. 6A(ii) and 6A(iii) are, respectively, an exploded view and a crosssection through a hub containing an embodiment of a coupling mechanismof the present invention, as well as a device inserted through thecoupling mechanism;

FIGS. 6B and 6C are, respectively, cross sectional views of a deviceinserted through an alternate embodiment of a coupling mechanism of thepresent invention and being removed therefrom;

FIG. 6D(i) is a side view of an alternative embodiment of a couplingmechanism of the present invention;

FIG. 6D(ii) shows a perspective view of a device partially insertedthrough an embodiment of a coupling mechanism of the present invention;

FIG. 6E(i) shows a side view of an embodiment of a cap of a hub;

FIG. 6E(ii) is a partial cross sectional view of an alternate embodimentof a coupling mechanism located within a hub;

FIGS. 6F(i) and 6F(ii) are, respectively, a cross section through, andan exploded view of, a hub containing an embodiment of a couplingmechanism of the present invention, as well as a device inserted throughthe coupling mechanism;

FIGS. 6F(iii) and 6F(iv) are, respectively, perspective views of adevice being inserted into a hub and being removed therefrom comprisingan embodiment of a coupling mechanism of the present invention;

FIGS. 7A, 7B and 7C illustrate top views of a coupling member inaccordance with an embodiment of the present invention in its differentstates;

FIG. 7D illustrates a side cross sectional view of a coupling member inaccordance with an embodiment of the present invention in its differentstates;

FIG. 8A is a perspective view of a coupling member in accordance with analternative embodiment of the present invention;

FIGS. 8B and 8C are different cross sectional views of the couplingmember taken along the mid-point of the coupling member of FIG. 8A, inaccordance with an alternative embodiment of the present invention.

FIGS. 8D(i) and 8D(ii) are a perspective view of a coupling member inaccordance with an alternative embodiment of the present invention;

FIGS. 8E(i), and 8E(iii) are a top view of a coupling member inaccordance with an embodiment of the present invention and a portion ofthe housing for retaining the same;

FIG. 8E(ii) is a perspective view of a coupling member in accordancewith an alternative embodiment of the present invention as well as aportion of the housing for retaining the same;

FIGS. 8F(i), and 8F(iii) are, respectively, cross sectional views of adevice inserted through an alternate embodiment of a coupling mechanismof the present invention and being removed therefrom;

FIG. 8F(ii) is a perspective view of a coupling member in accordancewith an alternative embodiment of the present invention as well as aportion of the housing for retaining the same;

FIGS. 9A and 9B are, respectively, an exploded view and a perspectiveview of an alternate embodiment of the first mating member containing anembodiment of a coupling mechanism of the present invention, as well asa device inserted through the coupling mechanism;

FIG. 9C is a perspective view of an alternate embodiment of the firstmating member comprising an embodiment of a coupling mechanism of thepresent invention, in accordance with an embodiment of the presentinvention;

FIGS. 9D and 9E are cross sectional views taken along different sectionsof the second mating member shown in FIG. 9C, that comprises anembodiment of a coupling mechanism of the present invention, as well asa device inserted through the coupling mechanism, in accordance with anembodiment of the present invention;

FIG. 10 is a perspective view of a first device coupled to a seconddevice where the first device comprises a hub cap with indicia, inaccordance with an embodiment of the present invention;

FIG. 11 is a perspective view of a coupling member of the presentinvention retained within a housing base portion of a first matingmember;

FIG. 12 is a cross sectional view of a first device and a second deviceillustrating the second device snagging during the removal;

FIG. 13A is a frontal view of the first mating member hub cap where thehub cap is symmetrical, without any indicia;

FIG. 13B is a frontal view of the first mating member hub cap where thehub cap is unsymmetrical, having indicia, in accordance with anembodiment of the present invention; and

FIGS. 14A and 14B are cross sectional views of the coupled first andsecond mating members wherein the first mating member comprises abeveled proximal face with a sharp inner edge and a rounded inner edge,respectively.

DETAILED DESCRIPTION

With specific reference now to the drawings in detail, it is stressedthat the particulars shown are by way of example and for purposes ofillustrative discussion of certain embodiments of the present inventiononly. Before explaining at least one embodiment of the invention indetail, it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangement of thecomponents set forth in the following description or illustrated in thedrawings. The invention is capable of other embodiments or of beingpracticed or carried out in various ways. Also, it is to be understoodthat the phraseology and terminology employed herein is for the purposeof description and should not be regarded as limiting.

In order to carry out certain medical procedures, such as trans-septalprocedures, it is necessary to gain access to the heart specifically tothe left atrium of the heart. Access may be obtained to the heart fromvasculature using one or more medical devices, such as an introducer orsheath. In order to gain access, a superior approach may be used (bygaining access to the heart, for example from the jugular vein throughthe superior vena cava), or alternatively access may be obtained fromthe femoral or inferior approach (by gaining access to the heart fromthe femoral vein through the inferior vena cava). Once access isobtained into the left atrium, one or more additional devices may beadvanced through the introducer or sheath to carry out a part of theprocedure. For example, in order to carry out a trans-septal puncture, apuncture device is advanced through vasculature in order to puncture aseptum of the heart to gain access to the left atrium. In some cases,the puncture device may be advanced through or with a sheath anddilator. Once the puncture device has punctured the septum, a dilatormay be advanced to dilate the hole. This allows larger medical devicesto be advanced through the puncture. In such procedures, the dilator maybe locked or coupled to an introducer or sheath using a couplingmechanism during a portion of the procedure, allowing the two devices tobe advanced concurrently and/or to enable two of the devices to becoupled together once they are properly positioned relative to oneanother. The coupling mechanism may also be decoupled during a part ofthe procedure so that the devices may be advanced independently.

In conventional systems, coupling mechanisms are provided that connecttwo devices at the proximal portions, thereof for example, along the hubportions, which ensures that the distal portions remain fixed in thedesired position while the user guides the sheath and dilator inside thepatient anatomy. In some such examples, the direction of the sheathcurve is indicated by the side port on the sheath hub and is controlledby rotating the sheath hub. The coupling mechanism couples the dilatorto the sheath allowing the sheath and dilator to be advanced and/orrotated together.

For example, once the devices are positioned at the septum prior topuncture, the dilator snaps into the sheath hub to connect the twodevices. This is done by the user on the proximal end. By connecting thetwo devices proximally, it ensures the distal portions remain fixed inthe desired position relative to one another while the user guides thesheath and dilator.

Certain limitations may be associated with the use of medical devices,such as introducers, sheaths, and dilators, that employ conventionalcoupling mechanisms, such as snaps. The limitations of the existingcoupling mechanisms on these devices are that the snaps degrade withuse, which may result in one or more of the following: insufficientretention force, insufficient tactile feedback, and/or generation ofdebris. Additionally, the coupling mechanism may not provide desiredinsertion force and/or removal force. In some such examples, it may betoo difficult to, or require too much force to, snap or connect the twodevices together, leading to difficulty when coupling the two devices.Similarly, it may require too much force to unsnap or disconnect the twodevices which could lead to loss of positioning of the devices.Conversely, it may be too easy to, or require very little force to, snapor connect the two devices together. Similarly, it may require verylittle force to unsnap or disconnect the two devices, providinginsufficient retention force, and potentially leading to undesiredand/or unintentional decoupling of the devices.

Conventional snap mechanisms require the use of plastic deformation,where the snaps are designed to, and require that, they deformplastically to enable coupling or locking of the two components. Suchmechanisms rely on degradation of the snap component to enable locking.The degradation of components results in the components not retainingtheir shape over multiple uses, leading to the component becomingdeformed or degraded over time. For example, a press fit between rigidrings, bumps, or tabs, may be used to couple two medical devices. Assuch, the initial insertion force value to enable coupling or lockingfor the first time may be high, however with multiple uses (even asearly as the second or third use) the insertion force required to insertthe dilator hub into the sheath hub may begin to decline rapidly. Theuser may need to use a very high force to snap the two devices initiallybut as the components degrade with multiple uses, the user will get adifferent feel, providing a varying and inconsistent user experience.The prior art snaps require the user to use a varying amount ofinsertion force to couple the sheath and dilator hubs together to snapthe two hubs together. This provides the user with varying feedback onthe force that is required in order to snap the two components together.

There exists a need to provide a coupling mechanism allowing two devicesto be coupled together, while providing a relatively uniform insertionforce and/or removal force. Furthermore, the coupling mechanism shouldnot degrade with multiple uses, as well as, provide sufficient retentionforce and tactile feedback.

Inventors of the present invention have developed a novel locking orcoupling mechanism for coupling or locking two medical devices and asystem that uses the same. The novel mechanism as provided herein is areleasable coupling or locking mechanism that provides a coupling memberor element such as a flexible coupling member that provides a flexiblecoupling at the interface between the two devices, for example at theinterface between the proximal portion of the two devices. In otherwords, in some embodiments of the present invention, a flexible couplingmember is provided that allows first and second mating members of acoupling system or arrangement to be releasably coupled to one another.

In one broad aspect, embodiments of the present invention include areleasable coupling mechanism for coupling a delivery catheter and adilator. The delivery catheter comprising a first mating member and thedilator comprising a second mating member. The second mating member ispositioned at a proximal end of the dilator and comprises a distal endand a proximal end. The first mating member positioned at a proximal endof the delivery catheter comprising a distal end and a proximal end. Theproximal end of the first mating member comprises a first coupling meansfor releasably receiving a second coupling means which is positioned ata distal end of the second mating member. The first mating memberfurther comprising a coupling member proximal of the proximal end of thefirst mating member; the coupling member comprising a pair of engagementmembers positioned on opposing sides of the coupling member andconfigured to releasably engage the second coupling means. The firstmating member further comprising at least one indicia perpendicular fromthe pair of engagement members. The indicia indicate an orientation ofthe first mating member such that the second mating member disengagesfrom the coupling member by simultaneously deflecting the pair ofengagement members.

As a feature of this aspect, some embodiments include indicia comprisingtactile indicia, visual indicia, or a combination of tactile and visualindicia. In some such embodiments, the tactile and visual indicia is atleast one beveled edge.

In some embodiments of the present invention, the coupling mechanism isoval shaped with the pair of engagement members extending inwardlytowards the center of the oval. In some such embodiments, the pair ofengagement members then deflect in a radial direction.

In some embodiments, the pair of engagement members are configured todeflect from a first state to a second state upon insertion of thesecond mating member, wherein the distance between the pair ofengagement members in the first state is less than the distance betweenthe engagement members in the second state. In some such embodiments,the engagement members are configured to return to the first state uponremoval of the second mating member.

In another embodiment of the present invention, the second mating membercomprises a lip at the distal end, and a groove proximal to the lip. Thegroove has a diameter less than the diameter of the lip, wherein whenthe second mating member is inserted, the lip deflects the pair ofengagement members from the first state to the second state. As thesecond mating member is inserted further, the pair of engagement membersreturn to the first state, settling into the proximal groove, retainingthe pair of engagement members and coupling the first mating member andsecond mating member, enabling the delivery catheter and the dilator tobe advanced together throughout the transseptal procedure.

In some embodiments of the present invention, the first mating member issubstantially oval in the first state and substantially circular in thesecond state.

In some embodiments of the present invention, the first mating membercomprises a housing base and a cap, such that the coupling member iscontained within the housing base and the cap. The cap comprises anaperture configured to receive the second mating member and the capfurther comprises a beveled face from an outer edge to the aperture. Insome embodiments of the present invention, the beveled surface on adistal portion of the second mating member corresponds to the beveledface, whereby the beveled surface on the distal portion of the secondmating member is flushed.

In another broad aspect of the present invention, a delivery catheterfor advancing through a patient's vasculature and delivery of medicaldevices, comprises a first mating member positioned at a proximal end ofthe delivery catheter. The first mating member comprises a distal endand a proximal end. The proximal end of the first mating membercomprises a first coupling means configured to releasably receive asecond coupling means positioned at a distal end of a second matingmember, positioned at a proximal end of a dilator. The first matingmember additionally comprises a coupling member proximal of the proximalend; the coupling member comprising a pair of engagement memberspositioned on opposing sides of the coupling member and configured toreleasably engage the second coupling means. The first mating memberincludes at least one indicia, perpendicular from the pair of engagementmembers. The at least one indicia indicates an orientation of the firstmating member such that the second mating member disengages from thecoupling member by simultaneously deflecting the pair of engagementmembers.

In yet another broad aspect of the invention, a dilator for dilating atissue and for use with a delivery catheter comprises, a second matingmember positioned at a proximal end of the dilator. The second matingmember comprises a second coupling means positioned at a distal end ofthe second mating member. The second coupling means is configured to bereleasably inserted into a first coupling means of a first matingmember. The first mating member is at a proximal end of the deliverycatheter and wherein the first mating member comprises a coupling memberproximal to the proximal end of the first mating member. The couplingmember comprising a pair of engagement members positioned on opposingsides of the coupling member and configured to releasably engage thesecond coupling means. The first mating member comprises at least oneindicia on the first mating member, perpendicular from the pair ofengagement members; whereby the indicia indicates an orientation of thefirst mating member such that the second mating member disengages fromthe coupling member by simultaneously deflecting the pair of engagementmembers.

A Releasable Coupling Mechanism

In some embodiments of the present invention as shown in FIG. 1A, areleasable coupling mechanism 300 is provided for releasably couplingtwo members such as a first mating member 100 and a second mating member200. As additionally shown in FIGS. 1B and 1C, the releasable couplingmechanism 300 comprises a coupling member or component 1000 associatedwith a first mating member 100 for releasably coupling or engaging asecond mating member 200 to the first mating member 100, where thesecond mating member 200 is receivable by the first mating member 100,for example through an opening 112 thereof. In some such examples, thecoupling member 1000 is positioned inside or held within the firstmating member 100, as shown in FIG. 1B.

In some such embodiments, the coupling member 1000 has a first state1000A and a second state 1000B (shown in FIGS. 7A-7B) and is moveablethere-between to enable the second mating member 200 to be coupled tothe first mating member 100. Specifically, the coupling member 1000 ismoveable from the first state 1000A into a second state 1000B uponinsertion of the second mating member 200 into the first mating member100 to allow passage of the second mating member 200. The couplingmember 1000 is moveable thereafter into the first state 1000A to couplethe second mating member 200 to the first mating member 100, discussedfurther herein below.

The first state of the coupling member 1000 is the distance between theengagement members when no force is being applied to the couplingmember. In an embodiment, the distance between the engagement members isless than the diameter of the opening 112 of the first mating member100. For example, with reference to FIG. 7A, the distance between theengagement members, such as snaps 1630, of the oval shaped couplingmember 1600 is less than the diameter of the opening 112. The secondstate of the coupling member 1000 is the distance between the engagementmembers when a force is being applied by a second mating member as it isbeing advanced therethrough. In this second state, the distance betweenthe engagement members is substantially equivalent to (or greater than)the diameter of the opening of the first mating member. With referencenow to FIG. 7B, the distance between the engagement members, such assnaps 1630, of the oval shaped coupling member 1600 is substantiallyequal to the diameter of the opening.

Releasable Coupling Assembly

In accordance with some embodiments of the present invention, areleasable coupling assembly 400 is provided that comprises the firstmating member 100 and a coupling mechanism 300, as shown in FIGS. 1A-1C.More specifically, the releasable coupling assembly 400 comprises, thefirst mating member 100 and a coupling mechanism 300.

Releasable Coupling System

With reference to FIGS. 1A and 1D, a coupling system 500 comprises afirst mating member 100, a coupling mechanism 300, wherein the couplingmechanism 300 comprises a coupling member 1000, and a second matingmember 200. For example, the coupling system 500 comprises a releasablecoupling mechanism 300 that allows for releasably coupling two medicaldevices 102, 202, such a delivery catheter, for example as a sheath 120,and a dilator 220.

In one such embodiment, the first mating member 100 comprises a handleportion 110, such as a handle on a sheath 120. With reference to FIG.1A-1D, the handle 110 comprises a sheath hub 122 defining a housing 124;the housing 124 comprises an opening 112 for receiving the second matingmember 200 positioned on a dilator 220. In some embodiments, thecoupling member 1000 is coupled to the housing 124 of the first matingmember 100. In an embodiment, the coupling member 1000 may notnecessarily be directly attached or coupled to the housing 124 but isfunctional to interact with the housing 124 upon insertion or removal ofa second mating member 200 from the first mating member 100.

The releasable coupling system 500 additionally comprises a secondmating member 200 that is configured to be inserted within and receivedby the first mating member 100. In some such embodiments, the secondmating member 200 comprises a handle portion 210 of a second device 202(see, for example, a dilator 220 shown in FIGS. 1C and 1D) that isreceived by the opening 112 of the first mating member 100 of a firstdevice (see, for example, a sheath 120). The handle portion 210comprises a dilator hub 222 comprising a wider portion 226 (for examplesuch as ridge, a lip, a bump, or a ring 228), and a handle grooveportion 224 (as shown in FIGS. 2A(i), 2A(ii)) for receiving a portion ofthe coupling member 1000. For example, as illustrated in FIG. 6A(iii),the groove portion 224 would receive the snaps 1630 of an oval shapedcoupling member 1600.

In accordance with a releasable coupling system 500 of the presentinvention, the coupling member 1000 defines a first correspondingco-operative feature 1006 (as shown in FIG. 6D(i)). The firstcorresponding co-operative feature 1006 comprises engagement members,such as snaps 1030 (also indicated as 1630 on FIG. 6D(i)). A secondcorresponding co-operative feature 206 is provided on the second matingmember 200. In some examples, the second mating member 200 comprises agroove 226, as shown in FIGS. 6B and 2A(i)-2A(ii). The firstcorresponding co-operative feature 1006 of the coupling member 1000 isoperable to co-operatively engage the second corresponding co-operativefeature 206 of the second mating member 200 for releasably coupling thefirst and second mating members 100, 200.

In some such embodiments of the releasable coupling system 500, thereleasable coupling mechanism 300 comprises a translational lockingmechanism. For example, in the case of a sheath 120, a housing baseportion 124 b and sheath hub cap 126 define the housing 124. The sheathhub 122 comprises a hub portion 125 that is coupled to the housing 124.The housing 124 interacts with the coupling member 1000 to preventtranslational movement of the second mating member 200 with respect tothe first mating member 100. As shown in FIGS. 6A(iii) and 6A(iv), thecoupling member 1000 interacts by co-operatively engaging (at leastfunctionally) with the second mating member 200 The housing 124interacts to prevent movement of the coupling member 1000translationally in the proximal and distal directions. Specifically, thesheath hub cap 126 prevents proximal retraction of the second matingmember 200 and the housing base portion 124 b prevents distal movementof the second mating member 200, thereby preventing further advancement.

General Coupling Member Housing

As described herein above, some embodiments of the present inventionprovide a releasable coupling mechanism 300 which comprises a housing124 of the first mating member 100. The coupling member 1000 isfunctionally coupled to the housing 124 of the first mating member 100to retain the second mating member 200 once it is inserted into thehousing 124. For example, as shown in FIGS. 1A-1D, the coupling member1000 is held within the housing 124 of the first mating member 100. Thecoupling member 1000 is configured to interact with the housing 124 toprevent removal of the second mating member 200 in the absence of forceand to prevent translational movement of the coupling member 1000. In anembodiment, the coupling member 1000 abuts against the proximal innersurface of the housing 124 or a distal inner surface of the housing 124to prevent translation thereof.

In some such examples, the coupling member 1000 is attached to thehousing 124. These examples are shown in FIGS. 2A-2B, as well as FIGS.3A-3C, 4A-4C, FIGS. 5A-5F.

Engagement Member of the Coupling Member

The coupling member 1000 of the coupling mechanism 300 comprises atleast two engagement members. The at least two engagement members may beprotrusions, such as snaps, extending from a surface of a straightcantilever, a u-shaped cantilever, or retaining arms.

Straight Cantilever Embodiment

With specific reference now to FIGS. 2A(i)-2A(ii), and 2B(i)-2B(ii), thecoupling member 1000 is formed integrally with the housing 124 of thefirst mating member 100. In some such embodiments of a releasablecoupling mechanism 300, the coupling member 1000 comprises at least onecantilever 1010. The at least one cantilever 1010 comprises at least onestraight cantilever 1200 and is formed integrally with the housing 124,for example with a cap 126. In an embodiment, the straight cantilever1200 is movable from a first state 1000A (as shown in FIG. 2A(i)), intoa second state 1000B (as shown by directional arrows R). This allows thesecond mating member 200 to pass through the opening 112 of the firstmating member 100. The straight cantilever 1200 then returns to a firststate 1000A. The at least one straight cantilever comprises one or moreretaining arms 1212 as shown in FIG. 2A(i). In some such embodiments,the one or more retaining arms 1212 terminate in one or more engagementmembers, for example snaps 1230. With regards to FIG. 2B(ii), theembodiment comprises two straight cantilevers 1200 x, 1200 y which aredeflectable (i.e., deflect radially outward) to move from the firststate 1000A into the second state 1000B upon insertion of the secondmating member 200. The straight cantilevers 1200 are moveable in a planeP1 that is substantially in plane with the direction of advancement D ofthe secondary mating member 200 into the housing 124 for insertiontherein. The two straight cantilevers 1200 x, 1200 y can returnthereafter into the first state 1000A to couple the second mating member200 to the first mating member 100.

U-shaped Cantilever Embodiment

With reference now to FIGS. 3A(i)-3C, 4A-4C, FIGS. 5A-5F, the at leastone cantilever 1010 are u-shaped cantilevers 1300. With specificreference now to FIGS. 3A(i) and 3A(iii), as well as FIGS. 3D(i) and3D(ii), the one or more u-shaped cantilevers 1300 are held within thehousing 124. In some examples, the housing base portion 124 b is coupledto a hub portion 125. The u-shaped cantilevers 1300 are held within andcoupled to the housing base portion 124 b. In some such embodiments, theu-shaped cantilevers 1300 are exposed along a proximal face, forming theproximal outer face of the first mating member 100 as shown in FIG.3A(ii).

As shown in FIGS. 5A(i) and 5A(iii), the u-shaped cantilevers 1300 aresubstantially contained within or retained by the housing 124 (definedby the housing base 124 b and cap 126). The housing base portion 124 bis formed integrally with the hub cap 126, and thus the housing 124 ofthe first mating member 100, is formed integrally as a substantiallyunitary construction or piece. As such, the u-shaped cantilevers 1300may be contained within the integrally formed housing 124.

Alternatively, as shown in FIGS. 5D(i)-5D(iv), the housing 124 is formedfrom a two parts, comprising a housing base 124 b and a separate hub cap126 that are coupled together for example using a snap fit arrangement(as shown in FIG. 5E(i)). As such, the housing 124 comprises a housingbase 124 b and hub cap 126 and the u-shaped cantilevers are containedwithin.

As shown in FIGS. 3A(i)-3D(ii), 4A(i)-4C, 5A(i)-5F(ii), the u-shapedcantilever 1300 comprises moveable cantilever arms 1312. In someexamples, the u-shaped cantilevers 1300 are composed of a flexiblematerial, enabling the cantilever arms 1312 to flex between the firststate 1000A and the second state 1000B. For example, the u-shapedcantilevers 1300 are composed of an elastically deformable material,wherein the material remains in the elastic region of the strain curve.In an alternative embodiment, the u-shaped cantilevers 1300 may becomposed of a resilient material.

The pair of u-shaped cantilevers 1300 are moveable in a plane P1 (asshown in FIG. 3B, 3C, 4B, 4C, 5B, 5C) that is substantially in planewith the direction D of advancement of secondary mating member into thehousing for insertion or removal. Alternatively, in some embodiments,the pair of u-shaped cantilevers 1300 are moveable in a plane P2 that isperpendicular to the direction D of advancement of second matingmember200 into the housing 124 for insertion or removal (into and out ofFIG. 3B).

The u-shaped cantilevers 1300 have retaining snap arms 1312 thatterminate engagement members, such as snaps 1330, as shown in FIGS. 3B,3C, 4B, 4C and 5B, 5C. The snaps 1330 may comprise dual ramps 1333A,1333B, where the first ramp 1333A defines an insertion ramp angle andthe second ramp 1333B defines a removal ramp angle. The insertion rampangle and removal ramp angle create a component of force required forinsertion Fi and removal Fr that compresses the snaps 1330. In some suchexamples, the angles on the first and second ramps 1333A, 1333B may bevaried to define respective insertion and removal forces. In someinstances, the force may be varied by a moment created on the snap arm1312. Specifically, as shown in FIGS. 3B, 5B and 5F(i), as the secondmating member 200 is advanced into the first mating member 100, theinsertion force Fi will create a moment on the snap arm 1312 which willincrease the force required to move the u-shaped cantilever1300 from itsfirst state1000A into its second state 1000B. In some embodiments, theu-shaped cantilever1300, is effectively biased in first state 1000A, andthe moment on the snap arm 1312 will effectively increase the forcerequired to overcome this bias in order to move the u-shaped cantilever1300 into its second state 1000B. Conversely, upon removal of the secondmating member 200 from the first mating member 100 as shown in FIG. 3C(and additionally FIGS. 5C and 5F(ii)), the removal force will create amoment on the snap arm 1312, which will decrease the force required tomove the u-shaped cantilever1300 from its first state1000A into itssecond state1000B. In other words, the u-shaped cantilever1300, iseffectively biased in first state 1000A, and the moment on the snap arm1312 will effectively decrease the force required to overcome this biasin order to move the u-shaped cantilever1300 into its second state1000B. In some such embodiments, the angle of the second or removal ramp1333B may be provided as a relatively steep angle.

In other examples, the first and second ramps 1333A, 1333 b havesubstantially equivalent ramp angles defining substantially equivalentinsertion and removal forces Fi, Fr.

Inverted U-shaped Cantilever Embodiment

As illustrated in FIGS. 4A(i)-4A(iv), the u-shaped cantilevers 1300comprises a pair of inverted u-shaped cantilevers 1302 which may be heldwithin the housing 124, specifically the housing base portion 124 b, andform the proximal face of the first mating member 100 (specifically withreference to FIG. 4A(iv)). As was previously discussed, the first ramp1333A and second ramp 1333B may be different ramp angles, contributingto differing insertion and removal forces Fi, Fr. Conversely, the rampangles 1333A, 1333B may be substantially equivalent providing arelatively uniform insertion and removal force Fi, Fr.

Oval Shaped Coupling Member Embodiment

As shown in FIGS. 6A(i)-6F(iv), 7A-7D, 8A-8F(iii), and 9A-9E, areleasable coupling member 1000 is retained within the housing 124. Inthe embodiments shown the coupling member 1000 is substantially freefloating or loose within the housing 124. Specifically, with referenceto FIGS. 6A(i)-6F(iv), the coupling member 1000 comprises at leastcantilever 1010, as shown in FIG. 6D(i). The at least one cantilever1010 may comprise a simply supported beam configuration. For example,two substantially straight segments S may be coupled together using oneor more arcuate segments C, as shown in FIG. 8A. Each of the twostraight segments S of the cantilevers 1010 are coupled together at eachof their respective ends by an arcuate C segment. These substantiallystraight segments S, are deflectable portions that are defined by asimply supported beam configuration, where maximum deflection M is alongthe mid-point of the straight segments S. In some such examples, each ofthe deflectable portions comprise one or more retaining arms 1612 wherethe one or more retaining arms comprise one or more engagement members,such as snaps 1630.

In these types of embodiments, the coupling member 1000, may be formedas an oval shaped coupling member 1600, as illustrated in FIGS. 7A and7B. The oval shaped coupling member 1600 comprises one or more retainingarms 1612 that terminate in one or more engagement members, for examplesnaps 1630. The oval shaped coupling member 1600 may be in the form of asnap ring or band 1601.

In the embodiments illustrated in FIGS. 6A(i)-6F(iv), 7A-7D, 8A-8F(iii),9A-9E, the oval shaped coupling member 1600 is functionally coupled tothe housing 124, while remaining unattached or unengaged during use sothat it is moveable feely within the housing 124. Specifically, withreference to FIGS. 6D(ii), 6E(i) and 6E(ii), the oval shaped couplingmember 1600 is housed within the base portion 124 b of a sheath hub 122and is retained by the sheath hub cap 126. As such, the combination ofthe housing base portion 124 b and the sheath hub cap 126 form anenclosure to for the oval shaped coupling member 1600, as illustrated inFIG. 6F(i).

With reference now to FIGS. 6E(ii), and 6F(i) 6F(iv), the housing 124,as defined by housing base portion 124 b and sheath hub cap 126,interacts with the oval shaped coupling member 1600 to preventtranslational movement of the second mating member 200, with respect tothe first mating member 100, once the second mating member 200 isinserted into the first mating member 100. In some such examples, thehousing 124 interacts to prevent translational movement of the oval disccoupling member 1600 in the proximal and distal directions.Specifically, the sheath hub cap 126 prevents proximal retraction of thesecond mating member 200 and the base of the housing base portion 124 bprevents distal movement of the mating member 200.

As shown in FIGS. 6B and 6C, the oval shaped coupling member 1600 andthe snaps 1630 rub against the distal face 124 f of the housing baseportion 124 b. The resulting friction will increase the insertion forceas shown in FIG. 6B. Conversely, the oval shaped coupling member 1600and the snaps 1630 rub against the proximal face 126 f of the sheath hubcap 126. The resulting friction will increase the removal force.

The oval shaped coupling member 1600 may have an oval shapedconfiguration in its first state 1000A (FIG. 7A) and substantially roundshaped configuration in its second state 1000B (FIG. 7B). Thesubstantially oval shaped coupling member 1600, is deflectable to move(for example radially) from its oval shaped configuration in its firststate 1000A into its round shaped configuration in its second state1000B upon insertion of the second mating member 200 into the firstmating member 100. The oval shaped coupling member 1600, is capable ofreturning to the first state 1000A defined by the oval configuration tocouple the second mating member.

In some embodiments, the oval shaped coupling member 1600 is comprisedof a flexible material and, as such, the oval shaped coupling member1600 is elastically deformable to move between the first state 1000A andsecond state 1000B. The oval shaped coupling member 1600 may deflectradially outwards R into its round configuration 1000B upon insertion ofthe second mating member 200. The oval shaped coupling member 1600,moves outward to allow a raised portion of the second mating member 200,for example a bump, a lip, or a ring on the dilator hub 228, to advanceinto the housing 124 of the first mating member 100. The oval shapedcoupling member 1600 is moveable thereafter into its first ovalconfiguration 1000A to couple the second mating member 200 to the firstmating member 100. This is illustrated in FIGS. 6B, 6C, 8B, and 8C.

In some embodiments of the each of the pair of cantilevers 1010 of theoval shaped coupling member 1600 (as shown in FIG. 6D(i), FIG. 8A) ismoveable in a plane P2 that is perpendicular to the direction ofadvancement D of secondary mating member 200 into the housing 124 forinsertion. In some such embodiments, the snap force (i.e. the forcerequired for coupling the second mating member 200 to the first matingmember 100 using the coupling mechanism 300) is independent of theproximal length of the first mating member 100. As a result, thefrictional forces from insertion of the second mating member into thefirst mating member 100 against the coupling member 1000 can beminimized and as a result there is reduced drag. Thus, additionalfrictional forces are substantially not introduced and are not additiveto the snap force required to deflect the coupling member 1000 to enablecoupling. As such the insertion and removal forces are substantiallydetermined by the coupling member 1000. In some embodiments of thepresent invention, the insertion and removal force Fi, Fr are about 15N.

With reference now to FIG. 8F(i) and FIG. 8F(iii), the first matingmember 100, for example a first mating member found on a sheath 120, hasa hub 104 that further comprises a valve 150, wherein the oval shapedcoupling member 1600 may be oriented in a plane P2 that is perpendicularto the direction of advancement D of the second mating member 200 (asshown in FIG. 8A). In this orientation, the oval shaped coupling member1600 does not hinder the visibility of the valve 150 from the user. Inother words, in the orientation shown, the oval shaped coupling memberdoes not require use of the hub length L for the cantilever 1010lengths. In some such embodiments, the coupling mechanism 300 utilizesthe width of the housing 124, provided by the diameter of the housing124. This ensures that the snap force is independent of the hub lengthL. Additionally, this helps optimize visibility of the valve 150 throughthe opening 112 for the user by allowing it to be positioned in relativeproximity to the opening 112.

As previously described, the insertion and removal forces Fi, Fr areinfluenced by the insertion (first) and removal (second) ramps 1633A,1633B. These ramps 1633A, 1633B may have equivalent ramp angles which,in turn, produce substantially equivalent insertion and removal forcesrequired to compress the snaps 1630.

Conversely, the angles on the insertion and removal ramps 1633A, 1633Bmay be varied to define respective insertion and removal forces. In somesuch examples, the first and second ramps 1633A, 1633B have varying rampangles defining varying respective insertion and removal forces. Forexample FIG. 8C, provides a steeper angle on the first, insertion, ramp1633A compared to the ramp angle for the second, removal, ramp 1633B,which would increase the insertion force Fi in comparison to the removalforce. Thus, altering the insertion and removal ramp angles provides amechanism to tune the insertion and removal forces Fi, Fr. In order toensure the ramp angles are aligned within the housing correctly, theoval shaped coupling member 1600, may employ one or more orientationkeys 1480 provide a means for orienting the oval shaped coupling member1600 in the desired orientation. This may facilitate assembly where theremoval ramp angle may be different than the insertion ramp angle.

In some embodiments of the present invention, as shown in FIGS. 8D(ii),8E(ii) and 8E(iii), the snap force, defined by the insertion force Fiand the removal force Fr, can be changed by varying the wall thickness Tand the snap height. In some such examples, the snap overlap X isdefined as the overlap between the snap 1630 and the portion of thesecond mating member 200 that is inserted into the first mating member100. For example, in a dilator 220, this portion may comprise the ridge,bump, or lip 228, as well as the portion of dilator 220 defining thegroove 226 (as shown in FIG. 8F(ii)). In one such example, the wallthickness T is about 0.75 mm and the snap overlap X is about 0.5 mm. Inanother example, the wall thickness T is about 1.0 mm and the snapoverlap is about 1.0 mm.

The oval shaped coupling member 1600 may be comprised of an elasticmaterial, thus it remains in the elastic region upon deformation (i.e.,as it flexes between the first state 1000A and the second state 1000B).In some such embodiments of the present invention, the ability of theoval shaped coupling member 1600 to remain in the elastic region duringdeformation and flexion, facilitates having an insertion force Fi andremoval force Fr that are substantially uniform and remain substantiallyunchanged over multiple uses. In some examples, the oval shaped couplingmember 1600 can flex since it is free floating within the housing 124.This allows the sheath hub length L to be minimized since the flexing isin a radial direction. The oval shaped coupling member 1600 may beformed integrally, or in other words having continuous geometry, whichfacilitates in the reduction of stress concentrations of.

In some examples, the substantially oval shaped coupling member 1600 maybe composed of a resilient material such as a polycarbonate oracrylonitrile butadiene styrene (ABS). In some embodiments, the strainis substantially dependent on the structure. the strain seen by the ovalshaped coupling member 1600 during flexion is less than 6% (for plasticdeformation to occur, the oval shaped coupling member 1600 would requirea strain of greater than about 6%). The structure of the oval shapedcoupling member 1600 prevents the increase in strain by providingelastic deformation over multiple uses.

In an alternative embodiment the oval shaped coupling member 1600 isprovided in a first mating member 100 of a first medical device, such asa steerable sheath 190, as shown in FIGS. 9A-9E. The oval shapedcoupling member 1600 is contained or retained within the housing 124,defined by a housing base 124 b and a hub cap 126. The coupling memberis substantially free floating in the housing 124, where the oval shapedcoupling member 1600 is configured to couple a second mating member 200of a second medical device, such as a dilator 220, to the steerablesheath 190.

General Audible Feedback

In some embodiments of the present invention, the coupling members 1000,such as straight cantilever 1200, u-shaped 1300, and oval disc shaped1600, are configured to generate an audible feedback upon movementbetween the first state 1000A and second state 1000B. With reference toFIGS. 2A(ii), 2B(ii), 3B, 3C, 4B, 4C, 5B, and 5C, the coupling members1000 interact with the second mating member 200 upon insertion into thefirst mating member100. In some examples, the respective snaps 1230,1330 and 16300 of the respective coupling members interact with aportion of the second mating member 200, such as groove 226. Once thecoupling member returns from its second state 1000B to the first state1000A, an audible click is generated, indicating insertion and coupling.Similarly, the respective snaps 1230, 1330 and 16300 of the respectivecoupling members interact with a portion of the second mating member200, such as ridge or bump 228. Once the coupling member returns fromits second state 1000B to the first state 1000A, upon removal of thesecond mating member 200 from the first mating member 100, an audibleclick is generated, indicating removal and decoupling.

Indicia on Hub Cap

In some embodiments of the present invention, the hub cap 126 of thefirst mating member 100, for example on a sheath 120, may comprise atleast one indicia 128. The indicia 128 may be positioned on the outersurface of the base portion of the housing 124 b or of the hub cap 126(as shown in FIG. 10). A visual indicia, tactile indicia, or acombination of the two may be used. Visual indicia may be comprised of amarker of a different colour, such as an arrow, a line, or a dot, toname a few. Tactile indicators may comprise an embossed or debossedportion on the hub cap 126, for example a bump, line, shape, or maycomprise a beveled edge or lip. One example is illustrated in FIG. 10,where the indicia 128 comprises a pair of opposing beveled edges. Thebeveled edges extend from the outer surface 127 onto the proximal face129 of the hub cap 126. Alternatively, the indicia may be a combinationof the two types (i.e., both visual and tactile). For example, theindicia may comprise an embossed marker which is also denoted by adifferent colour.

The indicia 128 may be used to denote the orientation at which the usermay grip the handle to enable a smooth uncoupling of the first matingmember 100 of a first medical device from a second mating member 200 ofa second medical device (i.e., uncoupling a sheath 120 and dilator 220).In an embodiment, the coupling member 1000 and the housing base 124 bare functionally coupled. The hub cap 126 is positioned on top of thehousing base 124 b to retain the coupling member 1000 in the housing124. FIG. 11 illustrates an example of how the housing base 124 b andthe coupling member 1000 are positioned relative to one another. In thisembodiment, the coupling member is an oval shaped coupling member 1600.

During uncoupling, users may perform a “pinch and bend” technique wherethe dilator hub 222 (shown in FIG. 10) is pinched and bent, deflectingthe snaps and thereby uncoupling the two devices (i.e., a sheath 120 anda dilator 220). With reference again to FIG. 11, ideally the dilator hub222 is bent in the direction perpendicular (denoted by the Y arrows) tothe pair of snaps 1630 of the coupling member 1000. By doing so, thebend of the dilator hub 222 will cause both snaps 1630 to deflectsimultaneously. If the dilator hub 222 is bent in a different direction,for example along the line denoted by the X arrows, it may result in thedilator hub 222 snagging during uncoupling, this can be seen in FIG. 12.As the dilator hub 222 is bent into the direction of one of the snaps1630, the snap 1630 deflects outward R. This deflection outwards Rcauses a space to open between the coupling member 1600 and the innersurface of the hub cap 126. The ring, lip, or bump 228 on the dilatorhub 222 may then move into the space created, causing the ring, lip, orbump 228 to snag 232, for example, onto the inner edge 131 of the hubcap 126. In other words, if the dilator hub 222 is bent in a directionof a snap 1630, the oval shaped coupling member 1600 will benddisproportionately to one side (i.e., only one of the snaps 1630 willmove outwards), resulting in a gap created between the snap 1630 and theinside surface of the hub cap 126; the ring, lip, or bump 228 will moveinto the newly created gap, catching the inside edge 131 of the hub cap126 during uncoupling. In this situation, the catching of the ring, lip,or bump 228 may be exacerbated if the user has another device containedwithin the sheath 120 and dilator 220, for example a puncture device.The puncture device increases the stiffness of the system which resultsin the need for greater force being applied to the dilator hub 222 whenthe user performs the “pinch and bend” technique. This results in thesnap 1630 experiencing a higher compression force, causing an increasein deflection and creating an even larger gap between the snap 1630 andthe inside surface of the hub cap 126. With enough force, the ring, lip,or bump 228 can overcome the snag 232 and release which may result in a“two-step unsnap” wherein the ring, lip, or bump 228 is first releasedfrom the coupling member and then released from the snag 232. The“two-step unsnap”, although feasible, is less ideal as it isunpredictable and does not provide a consistent user experience.

One way to provide the user with information regarding positioning ofthe coupling member 1000, more specifically the positioning of the snaps1630 inside the housing 124, is to break the symmetry of the hub cap 126(a symmetrical hub cab 126 can be seen in FIG. 13A) by positioningindicia 128 on the hub cap. During the assembly of the housing 124, theindicia 128 can be used to ensure that the hub cap 126 is oriented suchthat the indicia 128 is aligned in a specific way to denote thepositioning of the snaps 1630, and thus, denotes the optimal benddirection to avoid the “two-step unsnap”. In the embodiment illustratedin FIG. 13B, the pair of indicia 128 are positioned perpendicular to thesnaps 1630, indicating to the user that they should bend the dilator hub222 in the direction of either indicia 128 (i.e., upwards or downwards);thus, avoiding bending into a snap 1630. In an alternative embodiment,the indicia may be positioned to indicate the position of the snap 1630.In such embodiments, a user would bend the dilator hub in a directionperpendicular to the indicia.

Beveled Proximal Face of the Second Mating Member

In some embodiments, the proximal face 129 of the first mating member100 of a first medical device, such as a sheath 120, may comprise abeveled proximal face 130, as seen in FIGS. 14A and 14B. The beveledproximal face 130 facilitates a smooth uncoupling by creating a sharpedge 136 (see FIG. 14A) or rounded edge 134 (see FIG. FB), therebycreating less chance for the ring, lip, or bump 228 to snag uponremoval. Additionally, the second mating member 200 of a second medicaldevice, such as a dilator 220, may comprise a dilator hub 222 with adistal portion comprising a beveled face 230 that corresponds to andengages with the first mating member 100 beveled proximal face 130. Thebeveled faces 130, 230, may be used in combination with the indicator128 to provide the user with smooth and consistent uncoupling process.Additionally, the beveled faces 130, 230, have the added benefit offacilitating the coupling of the dilator 220 into the sheath 120. Thebeveled face 130 of the hub cap 126 may act as a runway for the distaltip of the dilator 220 during insertion to guide the distal tip into alumen of sheath 120. Additionally, once the dilator hub is brought inproximity to the sheath hub, the beveled face 130 of the sheath hubguides the corresponding face beveled face 230 of the dilator hub sothat the respective mating members are aligned prior to coupling.

The embodiments of the invention described above are intended to beexemplary only. The scope of the invention is therefore intended to belimited solely by the scope of the appended claims.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable sub-combination.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the broad scope of theappended claims. All publications, patents and patent applicationsmentioned in this specification are herein incorporated in theirentirety by reference into the specification, to the same extent as ifeach individual publication, patent or patent application wasspecifically and individually indicated to be incorporated herein byreference. In addition, citation or identification of any reference inthis application shall not be construed as an admission that suchreference is available as prior art to the present invention.

1) A releasable coupling mechanism for coupling a delivery cathetercomprising a first mating member and a dilator comprising a secondmating member, enabling the delivery catheter and dilator to be coupledand advanced together, comprising: the second mating member positionedat a proximal end of the dilator, the second mating member comprising adistal end and a proximal end; the first mating member positioned at aproximal end of the delivery catheter comprising a distal end and aproximal end, wherein the proximal end of the first mating membercomprises a first coupling means for releasably receiving a secondcoupling means positioned at a distal end of the second mating member,the first mating member further comprising a coupling member proximal ofthe proximal end of the first mating member; the coupling membercomprising a pair of engagement members positioned on opposing sides ofthe coupling member and configured to releasably engage the secondcoupling means; and, the first mating member further comprising at leastone indicia perpendicular from the pair of engagement members; wherebythe indicia indicates an orientation of the first mating member suchthat the second mating member disengages from the coupling member bysimultaneously deflecting the pair of engagement members. 2) Thereleasable coupling mechanism of claim 1, wherein the indicia comprisestactile indicia, visual indicia, or tactile and visual indicia. 3) Thereleasable coupling mechanism of claim 2, wherein the tactile and visualindicia is at least one beveled edge. 4) The releasable couplingmechanism of claim 1, wherein the coupling member is oval, and the pairof engagement members extend inwardly towards the center of the oval. 5)The releasable coupling mechanism of claim 4, wherein the pair ofengagement members deflect in a radial direction. 6) The releasablecoupling mechanism of claim 1, wherein the pair of engagement membersare configured to deflect from a first state to a second state uponinsertion of the second mating member, wherein the distance between thepair of engagement members in the first state is less than the distancebetween the engagement members in the second state. 7) The releasablecoupling mechanism of claim 6, wherein the pair of engagement membersare configured to return to the first state upon removal of the secondmating member. 8) The releasable coupling mechanism of claim 6, whereinthe second mating member comprises a lip at the distal end, and a grooveproximal to the lip, the groove having a diameter less than the diameterof the lip, wherein when the second mating member is inserted, the lipdeflects the pair of engagement members from the first state to thesecond state, and wherein when the second mating member is insertedfurther the pair of engagement members return to the first state,settling into the proximal groove whereby the pair of engagement membersare retained, and whereby the first mating member and the second matingmember are coupled, enabling the delivery catheter and the dilator to beadvanced together throughout the transseptal procedure. 9) Thereleasable coupling mechanism of claim 6, wherein the coupling member issubstantially oval in the first state and wherein the coupling member issubstantially circular in the second state. 10) The releasable couplingmechanism of claim 1, wherein the first mating member comprises ahousing base and a cap such that the coupling member is contained withinthe housing base and the cap. 11) The releasable coupling mechanism ofclaim 10, wherein the cap comprises an aperture configured to receivethe second mating member and wherein the cap further comprises a beveledface from an outer edge to the aperture. 12) The releasable couplingmechanism of claim 11, wherein the second mating member comprises abeveled surface on a distal portion that corresponds to the beveled facewhereby the beveled surface on the distal portion of the second matingmember is flushed. 13) A delivery catheter for advancing through apatient's vasculature and delivery of medical devices, the deliverycatheter comprising: a first mating member positioned at a proximal endof the delivery catheter comprising, a distal end and a proximal end,wherein the proximal end of the first mating member comprises a firstcoupling means configured to releasably receive a second coupling meanspositioned at a distal end of a second mating member wherein the secondmating member is positioned at a proximal end of a dilator, a couplingmember proximal of the proximal end of the first mating member; thecoupling member comprising a pair of engagement members positioned onopposing sides of the coupling member and configured to releasablyengage the second coupling means; and, at least one indicia on the firstmating member, perpendicular from the pair of engagement members;whereby the indicia indicates an orientation of the first mating membersuch that the second mating member disengages from the coupling memberby simultaneously deflecting the pair of engagement members. 14) Adilator for dilating a tissue and for use with a delivery catheter, thedilator comprising: a second mating member positioned at a proximal endof the dilator comprising, a second coupling means positioned at adistal end of the second mating member wherein the second coupling meansis configured to be releasably inserted into a first coupling means of afirst mating member, wherein the first mating member is at a proximalend of the delivery catheter and wherein the first mating membercomprises a coupling member proximal to the proximal end of the firstmating member, the coupling member comprising a pair of engagementmembers positioned on opposing sides of the coupling member andconfigured to releasably engage the second coupling means, and at leastone indicia on the first mating member, perpendicular from the pair ofengagement members; whereby the indicia indicates an orientation of thefirst mating member such that the second mating member disengages fromthe coupling member by simultaneously deflecting the pair of engagementmembers.